And use “update_all_product_suppliers_path(@product)” for my form
path.

A simpler alternative would be to change ‘prod.resources’ to
‘prod.resource’ but that would make changes to individual
‘suppliers’ (e.g. via web service) harder and seems against the spirit
of RESTful design.

Creating/updating multiple records must be a common idiom, especially
with the new nested attributes work, so how do you do it?